Do you have questions about nutrition? Send them to us at comer@lavanguardia.es, our nutritionist Aitor Sánchez will solve all your doubts.

Hello good. I want to know how long I can leave the can of tuna in the fridge without it going bad, and if it is good to eat canned tuna many times a week. Thank you. (Juan Domínguez, reader)

Hello John,

Canned tuna in the fridge is a product that, especially if it is preserved in oil, can go rancid very quickly. Here the danger would not be so much microbiological, since it will take a while for pathogenic bacteria to develop on tuna preserved in oil. Although we cannot neglect ourselves in this sense, it is preferable to focus on avoiding transformations and the deterioration of the quality of the product due to oxidation and rancidity, since they will happen much sooner. In any case, it should not be open for more than 4-5 days in the fridge, and we should consume it before reaching that point.

As tuna is a blue fish and therefore fatty, even in natural preserves attention should be paid to this, contact with oxygen inside the fridge despite being at low temperatures will cause the fat in the product to go losing quality and becoming harmful as it spends more time in contact with the air.

For this reason, it is essential to cover it correctly and that we do not leave it in the open cans with which the product already comes, since they do not allow proper conservation in the medium-long term. I would recommend transferring it to a tupperware or small lunch box with little volume, so that there is not much air inside and where we try to cover most of the fish meat by the liquid or by the canning oil. This way it will be preserved much better and will maintain its nutritional properties and better flavor.

Regarding the frequency of weekly consumption, we know that it is not positive to abuse oily fish that are heavily contaminated with heavy metals, such as mercury. It is true that canned tuna is not usually bluefin tuna, which is a species that is much more contaminated with this heavy metal, however, we should also limit its weekly consumption as you can well deduce. Although public health precautions are usually aimed at the most vulnerable populations such as children and pregnant women, as a precaution it would not be recommended to exceed the consumption of four or five small cans of canned tuna per week.

Hello, I am writing to you because I saw that I could send you questions about food. My question is the following, can you drink liquids while eating? For example, having lunch with a glass of water. I ask this because I recently saw a video in which they said that it was not good to drink liquids while eating, since this hinders the work of enzymes in digestion or something like that (I am writing what I remember). So I would like to know if it is advisable to drink water or some other liquid with food or not. Greetings. (Alison Albornoz Vera, reader)

Hello Alison,

of course you can drink liquids during meals, it is even convenient to have a good relationship with that intake and a correct speed when eating food.

That information you read about the fact that it is not positive to drink liquids while eating is true, but only partially. We can get to dilute the enzymes and also that too much water in the stomach does not allow the gastric juices to work properly, but this occurs from very high volumes of water that are not the conventional hydration that we do during a meal. For this reason, he commented that it is somewhat alarmist information, because instead of focusing on transmitting that this effect occurs only if we “abuse” water, it can generate fear when drinking water or even hydrating in a conventional way.

Therefore, there is no need to be afraid of including water during meals as long as it is done in moderate quantities, such as a couple of glasses of water. If, on the other hand, we are close to 1 liter (4-5 glasses), this phenomenon could occur, but I insist once again that it is in non-regulatory cases when drinking water at lunch or dinner.